The quotation from Butler is not impenetrable, though I'd hate to have to read more than a few such sentences. But the notion that there was a golden age of academic writing without agenda seems unsound to me. An awful lot of the German historical writing of the hundred years before 1945 was pretty tendentious, wasn't it? And it may have been crystal clear in German, but what bits I've encountered in English make me doubt that.
I know what you mean. I remember reading a passage, in German, from something by Heidegger and looking up and saying to someone nearby, "My God, I actually understand what he's saying." Unfortunately, what that was turned out to be a commonplace made obscure by his use of his own terminology. It became clear to me once I realized that he was just using his own word for what all the rest of us knew to be "contingency."